package promotions

import "testing"

// TestEvaluatePartialCart exercises the stateless evaluation path used by
// POST /promotions/evaluate: items drive the total, qualifying effects apply,
// and near-miss rules surface as pending nudges.
func TestEvaluatePartialCart(t *testing.T) {
	svc := NewPromotionService(nil)
	rules := []PromotionRule{volymrabattRule()}
	now := timeZero()

	t.Run("items qualify for a tier", func(t *testing.T) {
		// 2 × 25 000 kr (incl. VAT) = 50 000 kr -> 9% tier.
		resp := svc.Evaluate(rules, EvaluateRequest{
			Now: &now,
			Items: []EvalItem{
				{Sku: "A", Quantity: 2, PriceIncVat: 2500000},
			},
		})
		if resp.TotalDiscount.IncVat != 450000 {
			t.Errorf("discount = %d, want 450000", resp.TotalDiscount.IncVat)
		}
		if len(resp.AppliedPromotions) != 1 || resp.AppliedPromotions[0].Pending {
			t.Fatalf("want 1 applied (non-pending) effect, got %+v", resp.AppliedPromotions)
		}
	})

	t.Run("total-only fallback surfaces a pending nudge", func(t *testing.T) {
		// No items, just a total below the entry tier.
		resp := svc.Evaluate(rules, EvaluateRequest{Now: &now, CartTotalIncVat: 1500000})
		if resp.TotalDiscount.IncVat != 0 {
			t.Errorf("nothing should apply, discount = %d", resp.TotalDiscount.IncVat)
		}
		if len(resp.AppliedPromotions) != 1 || !resp.AppliedPromotions[0].Pending {
			t.Fatalf("want 1 pending nudge, got %+v", resp.AppliedPromotions)
		}
		if got := resp.AppliedPromotions[0].Progress["remaining"]; got != int64(500000) {
			t.Errorf("remaining = %v, want 500000", got)
		}
	})
}